2020 Toyota Corolla engine problems

Filed Oct 9, 2026 · Acceleration, Electrical · FL

I am reporting a severe, recurring safety hazard on my 2020 Toyota Corolla. The vehicle suddenly displays 'Drive-Start Control Malfunction' and completely cuts off engine power in motion, leaving the car stranded in active traffic. This happened after accelerating from a STOP sign on a main avenue. This is an inherent manufacturing defect present since delivery. In total, this chronic electrical surge has burned through 6 batteries and 3 Engine Control Modules (ECMs) at different mileages. Within the first weeks of purchase, it burned its first battery, which was replaced at Toyota and documented under the VIN history. Dealer staff deceptively called it 'normal,' leading me to replace subsequent batteries at AutoZone. [XXX] Toyota received the vehicle 4 times for this exact failure under Service Advisor [XXX]. They replaced the ECM twice, replaced a destroyed battery on a third visit just 400 miles later, and during this fourth visit on XXX, they only diagnosed the current burned ECM. Under Order XXX, I paid for 4.5 hours of specialized diagnostic labor, but the shop negligently just swapped parts and ignored the root cause. On XXX, an Operations Chief from Toyota Corporate called me under active BEC Case #XXX. He issued a final, verbal denial for Goodwill assistance based solely on mileage and age. Crucially, the Operations Chief explicitly admitted during the call that Toyota does not know what is causing the ECMs to burn out and does not know how to perform the proper diagnostic procedure to isolate the electrical root cause. He gave me to understand that my only option was to pay to replace the computer again and just put the car back on the road without a real fix. He actively refused to provide this denial in writing, forcing an unsafe vehicle back onto public roads. I have all four invoices to prove this chronic pattern. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Oct 8, 2026 · Brakes, Engine · CA

What component or system failed or malfunctioned: complete slave cylinder failure resulting in loss of braking and ability to shift. Luckily I was traveling at a low rate of speed when this happened, but if this happens to anyone on the freeway or while turning against traffic for example they would have no control of their car and could be seriously injured. I took it to the dealership and they diagnosed it as a slave cylinder failure at only 70k miles. This is incredibly pre-mature. The vehicle has not been inspected by the manufacturer, only the dealership but I am trying to escalate the issue. No warnings at all, I regularly get my car serviced on there were no instances of the clutch acting strange or brakes losing power (because the clutch and brakes share the same fluid reservoir) prior to this incident.

Filed Oct 3, 2026 · Electrical, Engine · GA

My Engine Maintenance light came on around 59,400 miles for my Coolest Control valve !! Needed it to be replaced! Light won’t go off just had it serviced for an oil change before this started!!

Filed Aug 6, 2026 · Engine · CA

Part is the coolant bypass valve. Toyota has been taken to court but dealership claims now that I’m over 100k miles I can’t do it. There was also a second part about 10 years but I wasn’t clear on the details of the outcome. Toyota has acknowledged this issue in court but failed to do so at the customer level in my case. engine light came on at 97k and now I’m at 104k which is over that 100k mark. Issue is I’ve only take my car to Toyota for repairs. They have known about this but failed to repair or notify me of it. I would have immediately brought my car in at 97k if. I had known. This puts not only me but my 3 kids and entire family at risk every time i drive. This is known to the dealership and they been taken to court for failures to notify customers of this known defect. It’s been inspected by Toyota the last time I took it in about a week ago at 104k miles.

Filed Jun 7, 2026 · Engine · CA

A message came on the screen saying “engine maintenance required” and it’s not going away. Upon doing a google search, there is a common failure in the cooling system for these cars reported by a lot of owners.

Filed Apr 24, 2026 · Engine, Fuel system · 59,000 miles · PA

The contact owns a 2020 Toyota Corolla. The contact stated that while at a red light, the vehicle shut off with the check engine and several other unknown warning lights illuminated. The vehicle restarted after several attempts. The vehicle was taken to an independent mechanic and the failure was duplicated. The mechanic retrieved DTC: P1603; "Engine Stall History" (ECM recording an unexpected engine shutdown or a communication error with the Transmission Control Module (TCM). The mechanic associated the failure with the federal safety agency Campaign Number: 20V682000 (Fuel System, Gasoline) and referred the contact to the dealer for assistance. Several dealers were contacted, and the contact was informed that the VIN was not included in the recall. The manufacturer was not notified of the failure. The vehicle was not repaired. The failure mileage was approximately 59,000.

Filed Apr 8, 2026 · Engine · AL

Car shows the below message when A/C is turned on: Engine Maintenance Required Visit Your Dealer

Filed Dec 27, 2025 · Engine · NC

Engine coolant bypass valve

Filed Aug 27, 2025 · Engine · CA

I have experienced a message saying 'Engine Maintenance Required' and after experiencing the same instances as many people have online, it seems the engine coolant bypass valve is faulty and needs to be replaced. No code can be read using a code reader either.

Filed Aug 11, 2025 · Engine · MD

Engine Maintenace required light came on. I was told that my coolant bypass valve needed to be replaced. This is happening on all Toyota vehicles from 2018-2024 common issue but the repair to fix something that should be covered under warranty.